Mountain Whitefish Care “Prosopium Williamsoni”

Mountain whitefish

Last updated on July 4th, 2022 at 05:59 am

Mountain whitefish (Prosopium williamsoni) are freshwater fish found in the Columbia River Basin and tributaries from Oregon to southeastern British Colombia. It can be identified by its small, olive-brown body with darker patches on top of each pectoral fin ray and wedge-shaped head that is similar to other members of the genus.

Mountain whitefish are seasonal fish that spawn in late fall, with adults migrating downstream to spawning areas and larvae staying upstream for one to two years until they reach maturity. This migration pattern is set up by a large peak of water flow during the winter months when streams become more shallow enough for adult mountain whitefish to migrate downstream and spawn.

Mountain whitefish live in cold, deep lakes and streams. They have a large mouth with many teeth on the lower jaw that are used to catch their prey. These fish are found from Alaska to Montana and Oregon. The mountain whitefish is an important species for fisheries because it is one of the most popular freshwater game fishes in North America.

Mountain whitefish scientific name

The scientific name of a mountain whitefish is Prosopium williamsoni.

Origin and Distribution

Mountain whitefish

The distribution of the mountain whitefish is limited to Lake Superior and lower St. Mary’s River in Michigan, Minnesota, and Ontario; its range also includes parts of Quebec. The species was introduced into two lakes in New York by a fish stocking program (the former Conesus Lake, now designated as Indian Lake No. Two), but has not been detected elsewhere in the state.

The mountain whitefish is known to inhabit lakes, streams, and rivers with cool, clear water; warmer waters (25-27°C) are tolerated for short periods of time, but prolonged exposure will result in death. The species prefers sandy or rocky substrates over soft bottoms or submerged logs.

Species profile

Mountain whitefish

Mountain whitefish are found in the Rocky Mountains and the western United States. It’s also called bull trout, steelhead, and silver salmon.

It grows to 24 inches long with an average weight of one pound. The fish has some color variations: red-orange on its back; light yellow or brownish-gray along its sides; and brownish or black on its belly.

Mountain whitefish live in cold, clear lakes with gravel bottoms and rocky shores. They feed mainly on aquatic insects but will also prey on fish fry or larvae of other species (particularly trout), mollusks, small freshwater crustaceans such as crayfish and arthropods, and even small mammals.

Mountain whitefish live to about 15 years in the wild but only a few months in captivity. They spawn every two or three years at most; however, they may also reproduce when water temperatures are high enough and food is abundant (usually during spring). Females lay up to 40 eggs each time.

Plakat Betta Fish Care And Species Guide

In comparison to a rainbow trout, the mountain whitefish is smaller than its prey. The fish’s light coloration allows it to blend in with its surroundings and make it more difficult for predators to spot them when they are near rocks or vegetation. Their streamlined bodies allow them to move swiftly through their habitat while also enabling them to maneuver around obstructions in their way.

Color and appearance

A mountain whitefish can be recognized by its distinct silvery band, which contrasts with the dark back. The fish has a long dorsal fin that runs from before the gills to just past the tail fin and is usually faded or completely absent in older individuals. There’s also an anal fin located directly behind this dorsal that looks a little like a small version of the dorsal.

Mountain whitefish habitat

Mountain whitefish are typically found in cold, clear rivers and streams. They can often be found at the head of a pool or riffle area where they feed on insect larvae, crayfish, and other aquatic invertebrates. In response to seasonal changes in water temperature, mountain whitefishes will migrate up or downstream during the spawning season.

Many individuals have been found in the Kootenai River and other freshwater bodies of water throughout Montana such as Flathead Lake, Trout Creek, and Swan Valley Reservoir. Whitefish are also commonly caught by fly fishermen near Yellowstone National Park when fishing for trout or charr (whitefish can be identified because they do not have a red spot on their tail).

Mountain whitefish size

Mountain whitefish, also known as redband trout, are relatively small freshwater fish. They can grow to a maximum length of about 18 inches (46 cm), and weigh between 15-20 lbs (about seven kg).

Mountain whitefish identification

Mountain whitefish are easily identifiable because of the dark bars on their sides, especially near the tail. These fish have a rounded back and a small head with an upturned mouth. They range from eight to twelve inches in length (20-30cm). They live primarily in streams that flow into lakes or rivers. The season for catching mountain whitefish is typically in the late summer to early fall.

Life cycle

Mountain whitefish typically spawn in the spring, and their eggs hatch within four to six weeks.

The fish live about five years on average; however, some have been known to reach as much as twelve years of age. They generally live longer than other trout species because they don’t migrate downstream for spawning like rainbows and brown trout do.

Frontosa Cichlid (Cyphotilapia Frontosa)

The fish spawn in small, headwater streams that are usually less than three meters wide and have a gravel or pebble bottom with little to no current. The adults lay eggs under the rocks near the shoreline of these water bodies. Mountain whitefish fry begins life as pelagic breeders; they live in the open water column, feeding on zooplankton.

The fish live for five to ten years and grow from six inches long as a juvenile to around fourteen inches in length when they reach adulthood. The average weight of the mountain whitefish is 15-30 pounds; however, some have been recorded at up to 40 pounds. They do not typically get larger than those found in mountain lakes.

Are they peaceful or aggressive?

Mountain whitefish are mainly vegetarian and will not fight with other fish. They can eat insect larva, detritus, or algae to supplement their diet if they need more protein. These little creatures enjoy living in cold water so it is best to keep them around 40 degrees Fahrenheit at the most. Mountain Whitefish usually hang out near rocks or plants to help them blend in.

Mountain whitefish care

Mountain whitefish

What do mountain whitefish eat?

Mountain whitefish eat a variety of freshwater and saltwater insects, crustaceans, worms, mollusks, fish eggs. They also will feed on algae from the bottom of lakes when other food sources are unavailable.

Water condition

The mountain whitefish lives in the cold, clear waters of North America. When it is young, this fish can be found as deep as 300 meters below the surface but generally stays closer to the shoreline and shallower depths when older. This means that they are not exposed to much sunlight which makes them a dark color with an orange tinge.


Mountain whitefish spawn in the fall, usually from September to November. They prefer fast-moving streams with gravel or cobble bottom and moderate water temperature (about 50 degrees Fahrenheit). This is because they are intolerant of temperatures over about 65 degrees Fahrenheit. Spawning takes place at night on riffle bottoms where there is plenty of oxygen.

A few days after spawning they die off due to the cold water temperature. The eggs are wrapped in ova and fertilized. The eggs hatch in the riffles, with a lot of gravel or cobble pieces which may be why they are not found near river bottoms, but rather on riffle banks.

Sunshine Peacock Cichlid (Aulonocara Stuartgranti Maleri)


The lifespan of mountain whitefish is up to 20 years. Some live as long as 25-30, but these are rare cases.

Parasites and diseases

The whitefish has many parasites and diseases that it can be affected by. One of the most common is ich, a parasitic protozoan called Ichthyophthirius multifiliis (Ich). This parasite causes skin ulcers on the fish’s head, body, or fins, as well as lethargy and loss of appetite.

The other common parasites are typically protozoan, like Clostridium and Gyrodactylus erythreum; or trematode flatworms, such as Metorchis conjunctus (liver fluke) and Fasciola hepatica (liver fluke).


Mountain whitefish have many predators including trout, pike, and other large fish. They are also prey for bald eagles, coyotes, otters, and foxes.

How to catch mountain whitefish

Mountain whitefish can be caught using a variety of methods. They are most commonly caught by anglers on the surface with lures such as spoons, flies, spinners, and minnows. One technique is to fish in deep water near rocks or submerged timber where they feed off food deposited by other species (usually trout). The use of a boat or canoe is required for this technique.

Mountain whitefish are also caught by fly fishermen who cast large, flashy flies near the surface of deep pools where they feed on aquatic insects and other small fish. Large worms (cut bait) can be used as an attractant if fished in shallow water with a bobber, which is then set at a depth where the bait will be suspended just under the surface.

Mountain whitefish are sometimes caught in nets by people fishing for other fish and shellfish during low tide on rocky shores, or even by gathering them with their bare hands from shallow water while wading near shorelines.

Does it make good pets?

No, they do not make good pets. They need a lot of space and are often too aggressive for even experienced pet owners to handle.

Is whitefish a trout?

The answer is a resounding NO. Whitefish are not trout and should never be eaten raw, sushi-style. They have oily skin which can cause stomach upset if it isn’t cooked properly before eating (a good rule of thumb for any fish). Trout on the other hand usually has low-fat content and cooks up cleanly.

History of mountain whitefish

Mountain whitefish

The mountain whitefish, or coho salmon to some fishermen, is a medium-sized freshwater fish found throughout the United States. The first written record of this species was in 1817 near the Great Egg Harbor River and it has been reported in every state east of the Rocky Mountains. It also lives in parts of Canada and Mexico.

Labidochromis caeruleus (Yellow Lab Cichlid)

Mountain whitefish live in clear, cold streams with a moderate current but are rarely found in lakes or reservoirs because of warmer water temperatures which can lead to rapid growth rates that cause them to be less tasty. They tend to eat small invertebrates like insects, crustaceans, worms, and amphibians as well as small fish.

These species of freshwater fish are threatened by habitat loss, dams, and barriers that impede migration, pollution, invasive species such as the walleye or bluegill which eat its eggs and compete for food sources with it. Because mountain whitefish are found in so many different types of water bodies, they have evolved a wide range of behaviors to survive.

The mountain whitefish is a migratory species that can travel long distances in search of food and habitat. This makes them particularly susceptible to being captured by humans, who take advantage of their instinctual behavior by capturing the fish as they are on “the move.” The other main threat this species faces is pollution which can change the pH levels of water, making it undrinkable and unusable for other species.

The mountain whitefish is a member of the salmon family because they spawn in freshwater rivers and streams but migrate to saltwater estuaries or bays where most salmons go to reproduce.

Mountain whitefish vs lake whitefish

The two types of whitefish are quite different on a molecular level. The mountain variety has more protein and less fat than the lake type but also contains higher levels of mercury.

Mountain whitefish live in cool water with a pH typically below six or seven, while cape cod whitefishes inhabit warmer waters where they feed primarily on shrimp and other crustaceans.

Mountain whitefish are also more prone to spawning in rivers than lakes because of their high protein diet, while cape cod types spawn along the coast or further offshore where they feed on invertebrates like clams, worms, crabs, and squid.

The most distinctive difference between these two types is that mountain whitefish can spawn year-round.